Hi, BMI

Researchers estimate that by 2015 almost 75 percent of American adults will be obese. But how do they determine whether a body is underweight, healthy, overweight, or obese?

In this lesson we’ll explore the body mass index, or BMI, which uses height and weight measurements to help determine whether a person is at a “healthy” weight. We’ll use this formula to find out the weight statuses of celebrities, from Taylor Swift to Arnold Schwarzenegger, and discuss whether BMI is all it’s cracked up to be.

Students will

Evaluate the BMI formula and classify scores for different values of height and weight

Given a person with an “unhealthy” BMI, determine necessary weight loss or gain to reach “healthy” status

Describe qualitatively how changes in height and weight interact to produce changes in BMI

Compare BMI scores and apparent body composition for various pairs of people

Discuss effectiveness of BMI as a means of classifying “healthy” weight

Before you begin

Students should know there are twelve inches in a foot. In order to calculate the weight change necessary for a person to go from an unhealthy category to the “healthy” one, students will have to be able to solve equations in one variable of the form 18 = 2x / 32.

Note: Approximately 1 in 3 American children are overweight or obese, while many others struggle with eating disorders. Before beginning the lesson, you might remind students that this is a sensitive topic for many people, and that you expect their behavior to demonstrate understanding and empathy.

How many calories does a body burn? Students interpret and apply the formula for resting metabolic rate (RMR) in order to learn about how calories consumed from food, calories burned from exercise, and calories burned automatically contribute to a body's weight.

Like the jacket, this lesson is for Members only.

Some Free Lessons From Mathalicious

How do the rules of an election affect who wins? Students calculate (as a percent) how much of the electoral and popular vote different presidential candidates have received, and add with integers to explore elections under possible alternative voting systems.

Topic:
Number System (NS), Ratios and Proportional Relationships (RP), Reasoning with Equations and Inequalities (REI)